Conventional power system graphic applications use absolute coordinates approach, in which the objects are positioned with respect to a common origin. This can result in problems of re-adjustment and re-alignment in the network and substation diagrams when editing or merging the graphics. This paper introduces the notion of layouts and proposes a graphics model to facilitate positioning of graphical elements relative to each other in a hierarchy of layouts, thereby making the network diagrams flexible, sharable and extensible. This proposed graphics model, expressed in unified modeling language (UML), is shown to be compatible with the existing common information model (CIM) graphics model IEC 61970-453. Consequently, the need for extension of CIM graphics model is justified and an extension is proposed. Another key feature of the proposed model is configurability. Since the necessary parameters are explicitly modeled, the user only needs to provide configuration information describing the hierarchical connectivity of the substation or the network. The absolute coordinates can be calculated from the configuration and the power system diagrams can be auto-generated. This paper demonstrates the above benefits highlighting the technologies for implementation. Case study on 400-kV 20-substation diagrams of Maharashtra system in India is presented. © 2013 IEEE.